Quote - I have, at this point, 10 external runtimes.  The only content in the default runtimes is what's installed with each of my Poser installs.  My Runtimes are set up by character (V3, M3, D3, Sp3, MilKids, MilTeens, etc), also have one for hair, one for lights, one for characters I'm working on, and my biggest one, Props.  I have a runtime for 3rd party characters like Apollo Maximus by Anton and for the characters I get from Sixus1.  This keeps my content organized in a manner I can use quickly.

The advantage of multiple external runtimes is that when I load P6 I load with only the P6 runtime which is fairly empty.  I can, then, load and unload any of the external runtimes I need at the time.  I also close Poser with no external runtimes linked so my P6 opens in about 20 seconds.  Also, since all of my Runtimes are on an external USB 2 hard drive, I won't lose everything I've got installed if my comp crashes.  This is a big plus for me since my external runtimes total nearly 75 Gigs of content.

 

Pretty much the same setup as you have. I have something like 40 External Runtimes.
I even yanked the P5 and P6 Characters out of Poser 5 and Poser 6.

Cheers
DR

"That government is best which governs the least, because its people discipline themselves."
Thomas Jefferson